A conventional drive device for a thermal transfer printer of this type is shown in FIG. 5. The drive device includes a platen roller 2 to which a fixed pressure is applied by means of a thermal head 1. A mount 4 and an ink ribbon 5 put between the platen roller 2 and the thermal head 1. The mount 4 has labels 3 applied thereto. The platen roller 2 is driven to rotate so that the mount 4 and the ink ribbon 5 are fed only by a frictional force of the platen roller 2 upon such rotation.
In a drive system of such a conventional type, the mount 4 (label 3) may be caused to meander due to a delicate difference between pressing forces at left and right positions between the thermal head 1 and the platen roller 2, or the feeding amount of the labels may sometimes show variations because of slips in the friction drive, resulting in a bad quality of print on labels.